JP3591234B2 - Control valve for variable displacement compressor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control valve of a variable displacement compressor used in, for example, a vehicle air conditioning system.
[0002]
[Prior art]
This type of variable displacement compressor includes, for example, a control passage that connects a discharge pressure region and a crank chamber, and controls the discharge capacity by adjusting the pressure in the crank chamber to change the inclination angle of the cam plate. There is a known configuration.
[0003]
As a control valve for this conventional variable displacement compressor, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 4-119271. That is, as shown in FIG. 7, the valve chamber 101 is partitioned and formed on the distal end side of the valve housing 102. The valve chamber 101 is connected to the discharge pressure region via an upstream control passage 103, and has a valve hole 104 formed in the axial direction of the valve housing 102, a port 105 orthogonal to the valve hole 104, and a downstream side. The control passage 103 is connected to the crank chamber. A valve body 106 for opening and closing the valve hole 104 is housed in the valve chamber 101.
[0004]
The pressure sensing chamber 107 is formed adjacent to the valve chamber 101 and is connected to the suction pressure area. The pressure-sensitive member 108 is housed in the pressure-sensitive chamber 107. The pressure-sensitive rod guide hole 109 is provided continuously through the valve hole 104 with respect to a partition wall 102a of the valve housing 102 that partitions the valve chamber 101 and the pressure-sensitive chamber 107, and connects the two chambers 101 and 107. I have. The pressure-sensitive rod 110 is slidably inserted into the pressure-sensitive rod guide hole 109, and operatively connects the pressure-sensitive member 108 and the valve body 106. Therefore, the displacement of the pressure-sensitive member 108 responsive to the pressure of the suction refrigerant gas is transmitted to the valve body 106 via the pressure-sensitive rod 110.
[0005]
The solenoid 111 is joined to the proximal end of the valve housing 102 and is operatively connected to the valve 106 via a pressure-sensitive member 108. The solenoid unit 111 changes the attraction force between the fixed iron core 112 and the movable iron core 113 by the excitation and demagnetization, and changes the load applied to the valve body 106. Therefore, the opening degree of the control passage 103 is determined by the balance between the urging force from the solenoid 111, the urging force from the pressure-sensitive member 108, and the like.
[0006]
[Problems to be solved by the invention]
Here, the pressure-sensitive rod 110 and the pressure-sensitive rod guide hole 109 provide a gas leakage between the high-pressure side port 105 and the low-pressure side pressure-sensitive chamber 107 while ensuring smooth slidability. It is processed with great care so that it can be suppressed. However, a minute processing error is inevitable, and there is a difference between the port 105 side and the pressure-sensitive chamber 107 side in the size of the gap between the cylindrical outer surface of the pressure-sensitive rod 110 and the cylindrical inner surface of the pressure-sensitive rod guide hole 109. Occurs. In particular, when a difference that the port 105 side becomes small occurs in this gap, the pressure difference between the port 105 and the pressure-sensitive chamber 107 causes the cylinder outer surface of the pressure-sensitive rod 110 to be pressed against the cylindrical inner surface of the pressure-sensitive rod guide hole 109. A lateral force may be generated, and the sliding resistance between the pressure-sensitive rod 110 and the pressure-sensitive rod guide hole 109 is increased (fluid sticking phenomenon).
[0007]
In recent years, control valves have tended to reduce the size of the solenoid portion 111 in order to achieve downsizing of the compressor. Accordingly, the pressure-sensitive member 108 has been reduced in size accordingly, and the valve element 106 has been operated with a small force balance. It has become. Therefore, the control valve is easily affected by an increase in the sliding resistance between the pressure-sensitive rod 110 and the pressure-sensitive rod guide hole 109 due to the fluid sticking phenomenon described above. As a result, when the large pressure-sensitive member 108 is used, the sliding resistance, which can be almost neglected, causes hysteresis, causing a problem that the capacity controllability is greatly reduced.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the problems existing in the prior art described above, and has as its object to provide a variable displacement compressor in which fluid sticking does not occur between a rod and a rod guide hole. It is to provide a control valve.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a valve body that opens and closes a control passage, a drive unit that drives the valve body to open and close, and a partition wall that partitions the valve body side and the drive unit side are provided. A rod guide hole connecting the valve body side and the drive unit side; and a rod slidably inserted through the rod guide hole and operatively connecting the valve body and the drive unit. By making at least one of the inner peripheral surfaces of the hole a tapered surface, the gap between the outer peripheral surface of the rod and the inner peripheral surface of the rod guide hole is expanded toward either the valve body side or the high pressure side of the drive unit side. It is a control valve for a variable displacement type compressor configured.
[0010]
In this configuration, even if the axis of the rod is eccentric to the axis of the rod guide hole for some reason, a lateral force is generated in the rod in a direction opposite to the eccentric direction, and the eccentricity of the axis with respect to the rod guide hole is Corrected by return.
[0011]
In the invention according to claim 2, a plurality of the tapered surfaces are formed in the axial direction of the rod.
In this configuration, the cross-sectional area of passage between the outer peripheral surface of the rod and the inner peripheral surface of the rod guide hole is complicatedly changed in the axial direction, and a labyrinth seal-like operation is achieved. Therefore, pressure leakage between the high pressure side and the low pressure side is effectively prevented.
[0012]
According to the third aspect of the present invention, the outer peripheral surface of the rod is a tapered surface having a smaller diameter toward either the valve body side or the drive unit side toward the high pressure side.
In this configuration, for example, there is no trouble such that a rod guide hole is provided through the partition wall and a tool is inserted into the narrow rod guide hole to correct the inner peripheral surface to a tapered surface.
[0013]
According to the fourth aspect of the present invention, the valve body that opens and closes the control passage, the drive unit that opens and closes the valve body, and the partition wall that divides the valve body side and the drive unit side penetrate the valve body side and the drive unit. A rod guide hole for connecting the valve body and the drive unit to the valve body, the rod guide hole being slidably inserted into the rod guide hole, and at least an outer peripheral surface of the rod or an inner peripheral surface of the rod guide hole. On the other hand, it is a control valve for a variable displacement compressor in which an annular groove is formed in the circumferential direction.
[0014]
In this configuration, the circumferential pressure in the gap between the outer peripheral surface of the rod and the inner peripheral surface of the rod guide hole is made uniform by the annular groove. Therefore, the fluid sticking phenomenon does not occur between the rod and the rod insertion hole.
[0015]
According to the fifth aspect of the present invention, the driving unit includes a pressure-sensitive mechanism, and the pressure-sensitive mechanism is provided in the pressure-sensitive chamber connected to the suction pressure area or the control pressure chamber via the detection passage, and in the pressure-sensitive chamber. A pressure-sensitive member, wherein the rod is a pressure-sensitive rod, which operatively connects the pressure-sensitive member and the valve element.
[0016]
In this configuration, the pressure-sensitive member is displaced by the pressure in the suction pressure area or the control pressure chamber introduced into the pressure-sensitive chamber, and this displacement is transmitted to the valve body via the pressure-sensitive rod.
In the invention according to claim 6, the driving section includes a solenoid section, and the solenoid section operates a plunger housed in a plunger chamber by excitation and demagnetization, and the rod is a solenoid rod, which operatively connects the plunger and the valve body. Is what you do.
[0017]
In this configuration, the plunger is displaced by excitation and demagnetization of the solenoid portion, and the displacement is transmitted to the valve body via the solenoid rod.
In the invention according to claim 7, the driving section includes both a pressure-sensitive mechanism and a solenoid section.
[0018]
In this configuration, the degree of opening of the control passage by the valve body is determined by the balance between the urging force from the pressure-sensitive mechanism and the urging force from the solenoid.
In the invention according to claim 8, the control passage connects the discharge pressure region and the control pressure chamber.
[0019]
In this configuration, the discharge capacity is controlled by adjusting the amount of discharge refrigerant gas introduced into the control pressure chamber, and a high-pressure discharge refrigerant gas is circulated in the control valve. Therefore, the fluid sticking phenomenon that occurs between the rod and the rod guide hole causes the rod guide of the rod to be smaller than the control valve configured to control the discharge capacity of the compressor by adjusting the discharge amount of the refrigerant gas from the control pressure chamber. Increase the degree of pressing against the hole.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the first and second embodiments in which the present invention is embodied in a displacement control valve of a clutchless variable displacement compressor, and a third embodiment in which the present invention is embodied in a displacement control valve of another type of variable displacement compressor. The form will be described. In the second and third embodiments, only differences from the first embodiment will be described, and the same or corresponding members will be denoted by the same reference numerals and description thereof will be omitted.
[0021]
(1st Embodiment)
First, the configuration of the clutchless variable displacement compressor will be described.
As shown in FIG. 2, the front housing 11 is joined and fixed to a front end of the cylinder block 12. The rear housing 13 is fixedly joined to the rear end of the cylinder block 12 via a valve forming body 14. The crank chamber 15 as a control pressure chamber is defined by being surrounded by the front housing 11 and the cylinder block 12. The drive shaft 16 is rotatably supported between the front housing 11 and the cylinder block 12 so as to pass through the crank chamber 15. The pulley 17 is rotatably supported by the front housing 11. The pulley 17 is connected to a drive shaft 16, and is directly connected to a vehicle engine 20 as an external drive source via a belt 19 wound around the outer periphery thereof without using a clutch mechanism such as an electromagnetic clutch.
[0022]
The rotation support 22 is fixed to the drive shaft 16 in the crank chamber 15. The swash plate 23 as a cam plate is supported so as to be slidable and tiltable with respect to the drive shaft 16 in the direction of the axis L thereof. The hinge mechanism 24 is interposed between the rotary support 22 and the swash plate 23. The swash plate 23 can be tilted in the direction of the axis L of the drive shaft 16 by the hinge mechanism 24 and can rotate integrally with the drive shaft 16. When the center of the radius of the swash plate 23 moves toward the cylinder block 12, the inclination angle of the swash plate 23 decreases. The inclination reducing spring 26 is interposed between the rotary support 22 and the swash plate 23. The inclination reducing spring 26 urges the swash plate 23 in the direction of decreasing the inclination. The maximum inclination angle of the swash plate 23 is defined by the contact with the rotating support 22.
[0023]
As shown in FIG. 3, the housing hole 27 extends through the center of the cylinder block 12 in the direction of the axis L of the drive shaft 16. The blocking body 28 has a cylindrical shape and is slidably housed in the housing hole 27. The suction passage opening spring 29 is interposed between the end surface of the housing hole 27 and the blocking body 28 and urges the blocking body 28 toward the swash plate 23.
[0024]
The drive shaft 16 is inserted into the inside of the blocking body 28 with its rear end. The radial bearing 30 is interposed between the rear end of the drive shaft 16 and the inner peripheral surface of the blocking body 28 and is slidable with respect to the driving shaft 16 in the direction of the axis L with the blocking body 28.
[0025]
The suction passage 32 forming the suction pressure region is formed at the center of the rear housing 13 and the valve forming body 14. The suction passage 32 communicates with the housing hole 27, and a positioning surface 33 is formed around an opening that appears on the front surface of the valve forming body 14. The blocking surface 34 is formed on the distal end surface of the blocking member 28 and is moved toward and away from the positioning surface 33 by the movement of the blocking member 28. When the blocking surface 34 is in contact with the positioning surface 33, the communication between the suction passage 32 and the inner space of the housing hole 27 is blocked by the sealing action between the two.
[0026]
The thrust bearing 35 is interposed between the swash plate 23 and the blocking body 28 and is slidably supported on the drive shaft 16. The thrust bearing 35 is urged by the suction passage opening spring 29 and is always held between the swash plate 23 and the blocking body 28. Then, as the swash plate 23 tilts toward the blocking body 28, the tilt of the swash plate 23 is transmitted to the blocking body 28 via the thrust bearing 35. Accordingly, the blocking body 28 is moved toward the positioning surface 33 against the urging force of the suction passage opening spring 29, and the blocking body 28 contacts the positioning surface 33 with the blocking surface 34. In a state where the blocking surface 34 is in contact with the positioning surface 33, further tilting of the swash plate 23 is restricted. In this restricted state, the swash plate 23 has a minimum tilt angle slightly larger than 0 ° and Become.
[0027]
The cylinder bore 12a is formed through the cylinder block 12, and a single-headed piston 36 is housed in the cylinder bore 12a. The piston 36 is moored to the outer periphery of the swash plate 23 via the shoe 37, and reciprocates in the cylinder bore 12a by the rotational movement of the swash plate 23.
[0028]
The suction chamber 38 forming the suction pressure area and the discharge chamber 39 forming the discharge pressure area are formed separately in the rear housing 13. A suction port 40, a suction valve 41 for opening and closing the suction port 40, a discharge port 42, and a discharge valve 43 for opening and closing the discharge port 42 are formed on the valve body 14. Then, the refrigerant gas in the suction chamber 38 is sucked into the cylinder bore 12a via the suction port 40 and the suction valve 41 by the reciprocating operation of the piston 36. The refrigerant gas sucked into the cylinder bore 12a is compressed to a predetermined pressure by the forward movement of the piston 36, and is discharged to the discharge chamber 39 via the discharge port 42 and the discharge valve 43.
[0029]
The suction chamber 38 communicates with the housing hole 27 through a through hole 45 provided through the valve body 14. Then, when the blocking body 28 comes into contact with the positioning surface 33 with its blocking surface 34, the opening 45 is blocked from the suction passage 32. The passage 46 is formed in the axis of the drive shaft 16, and the crank chamber 25 communicates with the inner space of the shutoff 28 via the passage 46. The pressure release passage 47 penetrates the peripheral surface of the blocking body 28, and the internal space of the blocker 28 and the internal space of the housing hole 27 are communicated via the pressure release port 47.
[0030]
The control passage 48 communicates the discharge chamber 39 with the crank chamber 15. The capacity control valve 49 is interposed on the control passage 48. The pressure detection passage 50 is formed between the suction passage 32 and the capacity control valve 49.
[0031]
The suction passage 32 for introducing the refrigerant gas into the suction chamber 38 and the discharge flange 51 for discharging the refrigerant gas from the discharge chamber 39 are connected by an external refrigerant circuit 52. The condenser 53, the expansion valve 54 and the evaporator 55 are interposed on the external refrigerant circuit 52. The evaporator temperature sensor 56 is installed near the evaporator 55. The evaporator temperature sensor 56 detects the temperature in the evaporator 55, and the detected temperature information is sent to the control computer 57. A cabin temperature setting device 58 for setting the temperature in the cabin of the vehicle, a cabin temperature sensor 59 and an air conditioner switch 60 are connected to a control computer 57.
[0032]
The control computer 57 includes, for example, a room temperature specified in advance by the vehicle interior temperature setting device 58, a detected temperature obtained from the evaporator temperature sensor 56, a detected temperature obtained from the vehicle room temperature sensor 59, and ON or OFF from the air conditioner switch 60. An input current value is instructed to the drive circuit 61 based on an external signal such as an OFF signal. The drive circuit 61 outputs the commanded input current value to the capacity control valve 49. Other external signals include signals from an unillustrated outside air temperature sensor, an engine speed sensor, and the like, and the input current value is determined according to the environment of the vehicle.
[0033]
Next, the capacity control valve 49 will be described in detail.
As shown in FIGS. 1 to 3, the capacity control valve 49 is configured by joining a valve housing 71 and a solenoid portion 72 near the center. The valve chamber 73 is defined between the valve housing 71 and the solenoid 72. The valve chamber 73 is connected to the discharge chamber 39 via a valve chamber port 77 and an upstream control passage 48. The valve element 74 is housed in the valve chamber 73. The valve hole 75 is opened in the valve chamber 73 so as to face the valve element 74. The valve hole 75 is formed to extend in the axial direction of the valve housing 71. The forcible opening spring 76 is interposed between the valve body 74 and the inner wall surface of the valve chamber 73, and urges the valve body 74 in the opening direction of the valve hole 75.
[0034]
The pressure-sensitive chamber 84 is defined at the tip of the valve housing 71. The pressure detection passage 50 is connected to a pressure sensing chamber 84. Therefore, the pressure sensing chamber 84 is communicated with the suction passage 32 via the pressure detection port 86 and the pressure detection passage 50. A bellows 87 as a pressure-sensitive member is housed in a pressure-sensitive chamber 84.
[0035]
The pressure-sensitive rod guide hole 88 is provided through a partition wall 71 a of the valve housing 71 that partitions the pressure-sensitive chamber 84 and the valve chamber 73, and connects the pressure-sensitive chamber 84 and the valve chamber 73. The pressure-sensitive rod guide hole 88 is formed continuously with the valve hole 75. The pressure-sensitive rod 89 is slidably inserted into the pressure-sensitive rod guide hole 88, and its tip is fitted to the bellows 87. The pressure-sensitive rod 89 is formed integrally with the valve body 74 and operatively connects the bellows 87 and the valve body 74. The portion of the pressure-sensitive rod 89 connected to the valve body 74 has a small diameter in order to secure a passage for the refrigerant gas in the valve hole 75.
[0036]
The port 90 is formed between the valve chamber 73 and the pressure-sensitive chamber 84 on the partition wall 71a of the valve housing 71. The port 90 is orthogonal to the valve hole 75. The port 90 is connected to the crank chamber 15 via the downstream control passage 48. That is, the valve chamber port 77, the valve chamber 73, the valve hole 75, and the port 90 form a part of the control passage.
[0037]
The plunger chamber 91 is formed in a solenoid portion 72, and a fixed iron core 92 is fitted into an upper opening thereof so as to be separated from the valve chamber 73. The movable iron core 93 as a plunger has a substantially closed cylindrical shape, and is accommodated in the plunger chamber 91 so as to be able to reciprocate in the axial direction of the valve housing 71. The follower spring 94 is interposed between the movable iron core 93 and the bottom of the plunger chamber 91.
[0038]
The solenoid rod guide hole 95 is formed in a fixed iron core 92 as a partition wall, and connects the plunger chamber 91 and the valve chamber 73. The solenoid rod 96 is formed integrally with the valve body 74, and is slidably inserted into the solenoid rod guide hole 95. The end on the movable iron core 93 side of the solenoid rod 96 is in contact with the movable iron core 93 by the urging force of the forcible opening spring 76 and the follow-up spring 94. Therefore, the movable iron core 93 and the valve element 74 are operatively connected via the solenoid rod 96.
[0039]
The plunger chamber 91 is formed between the communication groove 81 formed on the side surface of the fixed iron core 92, the communication hole 82 formed in the valve housing 71, and the inner wall surface of the rear housing 13 when the capacity control valve 49 is mounted. The small chamber 83 communicates with the port 90. That is, the plunger chamber 91 has the same crank chamber pressure as the port 90.
[0040]
The cylindrical coil 97 is disposed outside the fixed iron core 92 and the movable iron core 93 so as to straddle both the iron cores 92 and 93. A predetermined current is supplied to the coil 97 from the drive circuit 61 based on a command from the control computer 57.
[0041]
As shown in an enlarged circle A in FIG. 1, a portion of the outer peripheral surface of the pressure-sensitive rod 89 that faces the inner peripheral surface 88a of the pressure-sensitive rod guide hole 88 is a cylindrical surface. It is constituted by a sealing surface 89a and a tapered surface 89b continuous with the sealing surface 89a on the port 90 side (valve body side) and having a smaller diameter toward the port 90 side. Therefore, the gap between the tapered surface 89b of the pressure-sensitive rod 89 and the inner peripheral surface 88a of the pressure-sensitive rod guide hole 88 is larger on the port 90 side than on the pressure-sensitive chamber 84 side (drive unit side).
[0042]
Similarly, as shown in the enlarged circle B, a portion of the outer peripheral surface of the solenoid rod 96 facing the inner peripheral surface 95a which is the cylindrical surface of the solenoid rod guide hole 95 includes a cylindrical sealing surface 96a and a sealing surface 96a. And a tapered surface 96b which is continuous on the valve chamber 73 side (valve body side) and has a smaller diameter toward the valve chamber 73 side. Therefore, the gap between the tapered surface 96b of the solenoid rod 96 and the inner peripheral surface 95a of the solenoid rod guide hole 95 is larger on the valve chamber 73 side than on the plunger chamber 91 side (drive unit side).
[0043]
The tapered surfaces 89b and 96b of the pressure-sensitive rod 89 and the solenoid rod 96 are machined so that the port 90 side and the valve chamber 73 side have small diameters including machining errors. That is, the feature of the present embodiment is that the outer peripheral surfaces of the rods 89 and 96 are machined so as to increase the gap between the inner peripheral surfaces 88a and 95a of the guide holes 88 and 95 toward the high pressure side. In the enlarged circles A and B, the slopes of the tapered surfaces 89b and 96b are exaggerated for easy understanding, but the diameter difference between the large-diameter side and the small-diameter side is actually several μm or less. It is about several tens of μm.
[0044]
Next, the operation of the capacity control valve 49 will be described.
When the detected temperature obtained from the cabin temperature sensor 59 is equal to or higher than the set temperature of the cabin temperature setter 58 with the air conditioner switch 60 turned on, the control computer 57 instructs the solenoid unit 72 to be excited. Then, a predetermined current is supplied to the coil 97 via the drive circuit 61, and an attractive force corresponding to the input current value is generated between the two iron cores 92 and 93. This suction force is transmitted to the valve body 74 as a force in a direction in which the opening degree of the valve hole 75 decreases, against the urging force of the forcible opening spring 76.
[0045]
On the other hand, when the solenoid 72 is excited, the bellows 87 is displaced in accordance with a change in suction pressure introduced from the suction passage 32 into the pressure sensing chamber 84 via the pressure detection passage 50. The bellows 87 responds to the suction pressure, and the displacement of the bellows 87 is transmitted to the valve body 74 via the pressure-sensitive rod 89. Therefore, the opening degree of the valve hole 75 of the displacement control valve 49 is determined by the balance between the urging force from the solenoid 72, the urging force from the bellows 87, and the urging force of the forcible opening spring 76.
[0046]
When the cooling load is large, for example, the difference between the temperature detected by the vehicle interior temperature sensor 59 and the temperature set by the vehicle interior temperature setting device 58 becomes large. The control computer 57 controls the input current value to change the set suction pressure based on the detected temperature and the set room temperature. That is, the control computer 57 instructs the drive circuit 61 to increase the input current value as the detected temperature increases. Therefore, the attraction force between the fixed iron core 92 and the movable iron core 93 increases, and the urging force in the direction of decreasing the set value of the opening degree of the valve hole 75 by the valve body 74 increases. Then, at a lower suction pressure, the valve body 75 opens and closes the valve hole 75. Therefore, the capacity control valve 49 operates so as to maintain a lower suction pressure by increasing the current value.
[0047]
When the opening degree of the valve hole 75 is reduced, the amount of the refrigerant gas flowing from the discharge chamber 39 to the crank chamber 15 via the control passage 48 is reduced. On the other hand, the refrigerant gas in the crank chamber 15 flows out to the suction chamber 38 via the passage 46, the pressure release port 47, the housing hole 27, and the port 45. For this reason, the pressure in the crank chamber 15 decreases. When the cooling load is large, the pressure in the suction chamber 38 is also high, and the difference between the pressure in the crank chamber 15 and the pressure in the cylinder bore 12a is small. For this reason, the inclination angle of the swash plate 23 increases.
[0048]
When the passage cross-sectional area in the control passage 48 is zero, that is, when the valve body 74 comes into contact with the inner wall surface of the valve chamber 73 with the end face 74a and the valve hole 75 is completely closed, the discharge chamber 39 moves from the discharge chamber 39 to the crank chamber 15. The supply of the high-pressure refrigerant gas to the pump is not performed. Then, the pressure in the crank chamber 15 becomes substantially the same as the pressure in the suction chamber 38, the inclination angle of the swash plate 23 becomes maximum, and the discharge capacity becomes maximum.
[0049]
Conversely, when the cooling load is small, for example, the difference between the temperature detected by the vehicle interior temperature sensor 59 and the temperature set by the vehicle interior temperature setting device 58 becomes small. The control computer 57 instructs the drive circuit 61 to decrease the input current value as the detected temperature is lower. For this reason, the suction force between the fixed iron core 92 and the movable iron core 93 is weakened, and the urging force in the direction of decreasing the set value of the opening degree of the valve hole 75 by the valve body 74 is reduced. Then, the valve hole 75 is opened and closed at a higher suction pressure. Therefore, the capacity control valve 49 operates so as to maintain a higher suction pressure by reducing the current value.
[0050]
If the opening degree of the valve hole 75 increases, the amount of refrigerant gas flowing from the discharge chamber 39 into the crank chamber 15 increases, and the pressure in the crank chamber 15 increases. When the cooling load is small, the pressure in the suction chamber 38 is low, and the difference between the pressure in the crank chamber 15 and the pressure in the cylinder bore 12a increases. For this reason, the inclination angle of the swash plate 23 is reduced.
[0051]
As the cooling load is approached, the temperature in the evaporator 55 decreases so as to approach the temperature at which frost occurs. When the temperature detected by the evaporator temperature sensor 56 becomes lower than the set temperature, the control computer 57 instructs the drive circuit 61 to demagnetize the solenoid 72. This set temperature reflects a situation in which frost is likely to occur in the evaporator 55. Then, the supply of current to the coil 97 is stopped, the solenoid 72 is demagnetized, and the attractive force between the fixed iron core 92 and the movable iron core 93 disappears.
[0052]
Therefore, the valve element 74 is moved downward by the urging force of the forcible opening spring 76 against the urging force of the follower spring 94 acting via the movable iron core 93. Then, the valve element 74 shifts to the opening position where the valve hole 75 is opened to the maximum. Therefore, a large amount of the high-pressure refrigerant gas in the discharge chamber 39 is supplied to the crank chamber 15 via the control passage 48, and the pressure in the crank chamber 15 increases. Due to the increase in the pressure in the crank chamber 15, as shown in FIG. 3, the inclination angle of the swash plate 23 shifts to the minimum inclination angle.
[0053]
Further, the control computer 57 instructs the demagnetization of the solenoid 72 based on the OFF signal of the air conditioner switch 60, and the inclination of the swash plate 23 also shifts to the minimum inclination by this demagnetization.
[0054]
As described above, the opening / closing operation of the capacity control valve 49 changes according to the magnitude of the input current value to the coil 97 of the solenoid unit 72. That is, when the input current value increases, the control passage 48 is opened and closed at a low suction pressure, and when the input current value decreases, the control passage 48 opens and closes at a high suction pressure. The compressor changes the inclination of the swash plate 23 so as to maintain the set suction pressure, and changes the discharge capacity.
[0055]
That is, the capacity control valve 49 has a role of changing the set value of the suction pressure by changing the input current value and a role of performing the minimum capacity operation regardless of the suction pressure. By providing such a capacity control valve 49, the compressor plays a role of changing the refrigeration capacity of the refrigeration circuit.
[0056]
When the inclination angle of the swash plate 23 is minimized, the blocking body 28 contacts the positioning surface 33 with the blocking surface 34, and the suction passage 32 is blocked. In this state, the passage cross-sectional area in the suction passage 32 becomes zero, and the flow of the refrigerant gas from the external refrigerant circuit 52 into the suction chamber 38 is prevented. The minimum inclination angle of the swash plate 23 is set to be slightly larger than 0 °. This minimum inclination state is brought about when the blocking body 28 is arranged at the closed position where the communication between the suction passage 32 and the accommodation hole 27 is blocked. The blocking member 28 is switched between the closed position and the open position separated from the closed position in conjunction with the tilt of the swash plate 23.
[0057]
Since the minimum inclination angle of the swash plate 23 is not 0 °, the refrigerant gas is discharged from the cylinder bore 12a to the discharge chamber 38 even in the minimum inclination state. The refrigerant gas discharged from the cylinder bore 12a into the discharge chamber 38 flows into the crank chamber 15 through the control passage 48. The refrigerant gas in the crank chamber 15 flows into the suction chamber 38 through the passage 46, the inside of the blocking body 28, the pressure release port 47, the housing hole 27, and the port 45. The refrigerant gas in the suction chamber 38 is sucked into the cylinder bore 12a and discharged again to the discharge chamber 39.
[0058]
That is, in the minimum inclination state, the discharge chamber 39, the control passage 48, the crank chamber 15, the passage 46, the inside of the shut-off body 28, the discharge port 47, the housing hole 27, the port 45, the suction pressure area are the discharge pressure areas. A circulation passage passing through the suction chamber 38 and the cylinder bore 12a is formed inside the compressor. A pressure difference occurs between the discharge chamber 39, the crank chamber 15, and the suction chamber 38. Therefore, the refrigerant gas circulates in the circulation passage, and the lubricating oil flowing together with the refrigerant gas lubricates each sliding portion in the compressor.
[0059]
The present embodiment having the above configuration has the following effects.
(1) The gap between the outer peripheral surface (89a, 89b) of the pressure-sensitive rod 89 and the inner peripheral surface 88a of the pressure-sensitive rod guide hole 88 is larger than the port 90 side, which is the high pressure side, than the pressure sensitive chamber 84 side, which is the low pressure side. Has become. Therefore, the fluid sticking phenomenon can be prevented from occurring between the pressure-sensitive rod 89 and the pressure-sensitive rod guide hole 88, and the hysteresis of the capacity control valve 49 can be reduced, thereby preventing the capacity controllability from lowering. As a result, the size of the solenoid portion 72 can be reduced, which contributes to downsizing of the compressor.
[0060]
That is, as shown in FIG. 4, when the axis of the pressure-sensitive rod 89 is eccentric with respect to the axis of the pressure-sensitive rod guide hole 88 for some reason, the outer peripheral surfaces (89a, 89b) of the pressure-sensitive rod 89 are pressure-sensitive. The pressure distribution on the right side of the drawing, in which the gap between the rod guide hole 88 and the inner peripheral surface 88a is narrowed, drops sharply when reaching the vicinity of the sealing surface 89a via the tapered surface 89b. On the other hand, the pressure distribution on the left side of the drawing where the gap between the outer peripheral surface (89a, 89b) of the pressure-sensitive rod 89 and the inner peripheral surface 88a of the pressure-sensitive rod guide hole 88 is wide is gentle from the tapered surface 89b to the entire sealing surface 89. Is dropped. Accordingly, a lateral force is generated in the pressure-sensitive rod 89 in a direction opposite to the eccentric direction, and the eccentricity of the axis with respect to the pressure-sensitive rod guide hole 88 is corrected by self-return.
[0061]
(2) The gap between the outer peripheral surface (96a, 96b) of the solenoid rod 96 and the inner peripheral surface 96a of the solenoid rod guide hole 96 is larger on the valve chamber 73 side which is the high pressure side than on the plunger chamber 91 side which is the low pressure side. I have. Accordingly, the same operation and effect as in the above (1) can be obtained.
[0062]
(3) The outer peripheral surfaces of the rods 89, 96 are machined into tapered surfaces 89b, 96b. Therefore, for example, the rod guide holes 88 and 95 are provided through the partition walls 71a and 92, and a tool is inserted into the narrow rod guide holes 88 and 95 to correct the inner peripheral surface to a tapered surface. No hassle.
[0063]
(4) The compressor has a configuration in which the discharge capacity is controlled by adjusting the amount of the discharged refrigerant gas introduced into the crank chamber 15. A high-pressure discharge refrigerant gas is introduced into the valve chamber 73 of the capacity control valve 49. ing. Therefore, the fluid sticking phenomenon that occurs between the solenoid rod 96 and the solenoid rod guide hole 95 causes the solenoid rod guide hole 96 of the solenoid rod 96 to be smaller than that of the compressor configured to adjust the discharge amount of the refrigerant gas from the crank chamber 15. To increase the degree of pressing. In the present embodiment embodied in the capacity control valve 49 of such a compressor, it is particularly effective to achieve the effect.
[0064]
(2nd Embodiment)
FIG. 5 shows a second embodiment. In the present embodiment, the pressure-sensitive rod 89 and the solenoid rod 96 have a plurality of tapered surfaces 89b, 96b in the axial direction. Accordingly, the gap between the tapered surfaces 89b and 96b and the inner peripheral surfaces 88a and 95a of the rod guide holes 88 and 95 is larger on the high pressure side (73, 90) than on the low pressure side (84, 91).
[0065]
In this embodiment, the same operation and effect as those of the first embodiment are obtained, and the passage interruption between the tapered surfaces 89b, 96b of the rods 89, 96 and the inner peripheral surfaces 88a, 95a of the rod guide holes 88, 95 is performed. The area is complicatedly changed in the axial direction, and a labyrinth-seal-like effect is achieved. Therefore, it is effective to prevent the refrigerant gas from leaking between the high pressure side (73, 90) and the low pressure side (84, 91), and the capacity controllability of the capacity control valve 49 is further improved.
[0066]
(Third embodiment)
FIG. 6 shows a third embodiment. Although not shown, the displacement control valve 98 of the present embodiment is used for a variable displacement compressor different from the variable displacement compressors of the first and second embodiments. The capacity control valve 98 has only a function as a pressure-sensitive valve, and a diaphragm 99 is used as a pressure-sensitive member.
[0067]
Now, as shown in the enlarged circle C, the pressure-sensitive rod 100 has a columnar shape, and operatively connects the valve body 74 and the diaphragm 99. The annular groove 100b is formed in the circumferential direction on the outer peripheral surface 100a of the pressure-sensitive rod 100 facing the pressure-sensitive rod insertion hole 88, and a plurality of annular grooves are arranged at predetermined intervals in the axial direction.
[0068]
The present embodiment having the above configuration has the following effects.
(1) In the gap between the outer peripheral surface 100a of the pressure-sensitive rod 100 and the inner peripheral surface 88a of the pressure-sensitive rod guide hole 88, the circumferential pressure is made uniform by the annular groove 100b. As a result, even if the axis of the pressure-sensitive rod 100 is eccentric with respect to the axis of the pressure-sensitive rod guide hole 88, the fluid sticking phenomenon does not occur between the pressure-sensitive rod 100 and the pressure-sensitive rod guide hole 88. . This embodiment also has the same effect as the effect (1) of the first embodiment.
[0069]
(2) The annular groove 100b is formed on the outer peripheral surface 100a side of the pressure-sensitive rod 100. Therefore, for example, it is troublesome to form the pressure-sensitive rod guide hole 88 through the partition wall 71a and insert a tool into the narrow pressure-sensitive rod guide hole 88 to form an annular groove in the inner peripheral surface 88a. Absent.
[0070]
The present invention can be implemented in the following modes without departing from the spirit of the present invention.
In the first and second embodiments, the tapered surface is formed on the rod guide holes 88 and 95, not on the rods 89 and 96, so that the outer peripheral surfaces of the rods 89 and 96 and the inside of the rod guide holes 88 and 95 are formed. The gap with the peripheral surface is configured so that the high pressure side is wider than the low pressure side. In this case, the diameter of the tapered surface increases toward the high pressure side.
[0071]
Similarly, by forming the tapered surface on both the rod 89, 96 side and the rod guide hole 88, 95 side, the gap between the outer peripheral surface of the rod 89, 96 and the inner peripheral surface of the rod guide hole 88, 95 is reduced. The high pressure side must be wider than the low pressure side.
[0072]
In the third embodiment, the annular groove is formed not on the outer peripheral surface 100a of the pressure-sensitive rod 100 but on the inner peripheral surface 88a of the pressure-sensitive rod guide hole 88.
Similarly, an annular groove is formed on the outer peripheral surface 100a of the pressure-sensitive rod 100 and the inner peripheral surface 88a of the pressure-sensitive rod guide hole 88.
[0073]
○ To be embodied in a control valve having only the solenoid valve function (72).
According to a technical idea that can be understood from the above embodiment, the control valve for a variable displacement compressor according to any one of claims 4 to 8, wherein the annular groove 99b is formed in the outer peripheral surface 100a of the rod 100.
[0074]
This facilitates the formation of the annular groove 100b.
[0075]
【The invention's effect】
According to the first and fourth to eighth aspects of the present invention, it is possible to prevent the fluid sticking phenomenon from occurring between the rod and the rod guide hole, reduce the hysteresis of the control valve, and reduce the capacity controllability. Can be prevented.
[0076]
According to the second aspect of the invention, the gap between the outer peripheral surface of the rod and the inner peripheral surface of the rod guide hole has a labyrinth seal effect, and effectively prevents the leakage of the refrigerant gas between the high pressure side and the low pressure side. Can be prevented.
[0077]
According to the third aspect of the present invention, for example, a trouble such that a rod guide hole is penetrated through the partition wall, a tool is inserted into the narrow rod guide hole, and the inner peripheral surface thereof is corrected into a tapered surface. Absent.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a displacement control valve.
FIG. 2 is a longitudinal sectional view of a clutchless variable displacement compressor.
FIG. 3 is an enlarged sectional view of a main part showing a minimum discharge capacity state of the compressor.
FIG. 4 is a schematic diagram illustrating an operation.
FIG. 5 is an enlarged sectional view of a main part showing a second embodiment.
FIG. 6 is a longitudinal sectional view of a displacement control valve according to a third embodiment.
FIG. 7 is a longitudinal sectional view showing a conventional capacity control valve.
[Explanation of symbols]
15, a crank chamber as a control pressure chamber, 32, a suction passage as a suction pressure area, 39, a discharge chamber as a discharge pressure area, 48, a control passage, 49, a capacity control valve, 71a, a partition wall, 72, a drive unit 74, a valve element, 84, a pressure-sensitive chamber that forms a drive unit, 87, a bellows, 88, a pressure-sensitive rod guide, 88a, an inner peripheral surface, 89, a pressure-sensitive rod, 89b, a tapered surface. , 92: fixed iron core as a partition wall, 95: solenoid rod guide hole, 95a: inner peripheral surface, 96: solenoid rod, 96b: tapered surface.

Claims (8)

By adjusting the opening degree of the control passage connecting the suction pressure area or the discharge pressure area and the control pressure chamber, in the control valve of the variable displacement compressor that changes the discharge capacity,
A valve body for opening and closing the control passage;
A drive unit for opening and closing the valve body,
A rod guide hole penetrating through a partition wall that partitions the valve body side and the drive unit side, and connects the valve body side and the drive unit side,
A rod that is slidably inserted into the rod guide hole and that operatively connects the valve body and the drive unit;
By making at least one of the outer peripheral surface of the rod and the inner peripheral surface of the rod guide hole a tapered surface, the gap between the outer peripheral surface of the rod and the inner peripheral surface of the rod guide hole is increased by the high pressure on either the valve body side or the drive unit side. A control valve for a variable displacement compressor that expands toward the side. The control valve for a variable displacement compressor according to claim 1, wherein a plurality of the tapered surfaces are formed in an axial direction of the rod. 3. The control valve for a variable displacement compressor according to claim 1, wherein an outer peripheral surface of the rod is a tapered surface having a smaller diameter toward a higher pressure side of a valve body side or a drive unit side. 4. By adjusting the opening degree of the control passage connecting the suction pressure area or the discharge pressure area and the control pressure chamber, in the control valve of the variable displacement compressor that changes the discharge capacity,
A valve body for opening and closing the control passage;
A drive unit for opening and closing the valve body,
A rod guide hole penetrating through a partition wall that partitions the valve body side and the drive unit side, and connects the valve body side and the drive unit side,
A rod that is slidably inserted into the rod guide hole and that operatively connects the valve body and the drive unit;
A control valve for a variable displacement compressor, wherein an annular groove is formed in at least one of an outer peripheral surface of a rod and an inner peripheral surface of a rod guide hole. The drive unit includes a pressure-sensitive mechanism, and the pressure-sensitive mechanism includes a pressure-sensitive chamber connected to a suction pressure area or a control pressure chamber via a pressure detection passage, and a pressure-sensitive member disposed in the pressure-sensitive chamber. The control valve for a variable displacement compressor according to any one of claims 1 to 4, wherein the rod is a pressure-sensitive rod and operatively connects the pressure-sensitive member and the valve body. The said drive part is provided with a solenoid part, The solenoid part operates the plunger accommodated in the plunger chamber by excitation / demagnetization, The said rod is a solenoid rod, The operative connection of a plunger and a valve body of Claims 1-5. The control valve for a variable displacement compressor according to any one of the above. 7. The control valve for a variable displacement compressor according to claim 6, wherein the drive unit includes both a pressure sensing mechanism and a solenoid unit. The variable displacement compressor according to any one of claims 1 to 7, wherein the control passage connects a discharge pressure region and a control pressure chamber.

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